v0.16

Updates

• Refactor typings
  (by @bryanforbes in 39f9f0d and @msullivan in 4a17549)

• Update Python 3.10 support, drop Python 3.5
  (by @elprans in fa35523 and 189b959)

Fixes

• Fix test_none_collisions on 32-bit systems (#69)
  (by @elprans in fa35523 for #69)

Misc

• Clarify the license of the included pythoncapi_compat.h header
  (by @elprans in 67c5edf for #64)

• Use cibuildwheel to build wheels (#70)
  (by @elprans in f671cb4 for #70)